Recent questions tagged heredity

Description : Production of genetically modified plants is both a boon and bane. Explain.

Last Answer : By genetically modifying plants we can increase the yield, improve the plant breeds, make them pest and disease resistant. We can also transfer nitrogen fixing gene. The greatest disadvantage of genetically modified plants is the sterility of seeds which is a threat to conservation of plant species.

Description : Give reason: Though biotechnology is a boon to mankind, it may cause serious threat in future. OR Mention the limitations of biotechnology.

Last Answer : a) The use of biotechnology in plants has resulted in seed sterility which causes severe threat to the conservation of plant species. b) Genetically modified foods are a threat to human and ... , moral and cultural problems. e) Cloning can be used for illegal purposes and destructive activities.

Description : Mention the applications of biotechnology.

Last Answer : a) Biotechnology helps in large scaled synthesis of life saving drugs like antibiotics, vaccines, artificial hormones. b) It helps in improvement of plant and animal breeds, pests and pathogen ... used to transfer nitrogen fixing gene from bacteria into plants which enable them to get nitrogen.

Description : Name the first clone and the person who developed it?

Last Answer : The first clone was a sheep called Dolly. It was developed by Dr.Wilmut.

Description : What is meant by cloning?

Last Answer : The group of molecules or cells or organism which is derived from the same parent by an asexual process is called a clone.

Description : What is meant by cloning?

Last Answer : The technique of obtaining genetically similar molecules, cells, tissues or organism from a common precursor invitro process is called cloning.

Description : What is DNA finger print?

Last Answer : The series of bands in the form of fingerprint with a unique pattern is called DNA finger print.

Description : On what basis the short fragments of DNA arrange themselves?

Last Answer : The short fragments of DNA get separated on the basis of their size and net electrical charge.

Description : Write the importance of gel electrophoresis during DNA finger print technology.

Last Answer : Gel electrophoresis helps to break down the DNA of an individual into short fragments from which a DNA finger print can be obtained.

Description : What is gel electrophoresis?

Last Answer : The technique of breaking down the DNA of individual into short segments using specific enzymes is called gel electrophoresis.

Description : Explain DNA finger print technology.

Last Answer : The technique in biotechnology used for identifying individuals by determining the genetic relationships is called DNA finger print technology. The technique involves breaking down the DNA of individual into short ... of size and net electrical charge. They get arranged to form a finger print.

Description : What is meant by DNA finger print technology?

Last Answer : The technique in biotechnology used for identifying individuals by determining the genetic relationships is called DNA finger print technology.

Description : Mention any two applications of recombinant DNA technology in a) Animals breeding b) Plant breeding

Last Answer : Recombinant DNA technology is used for improving the quality of animal breeds. It is used to transfer nitrogen fixing gene from the bacteria into plants to enable them to obtain nitrogen.

Description : Mention one application of recombinant DNA technology.

Last Answer : Recombinant DNA technology is used to transfer nitrogen fixing gene from bacteria into plants which enable them to get nitrogen.

Description : What is meant by recombinant DNA technology?

Last Answer : The technique of manipulating the genes in the laboratory is called recombinant DNA technology. It involves the separation of desirable or useful gene from a cell and introduce it into another cell where it is made to express.

Description : What is meant by genetic engineering?

Last Answer : The technique of inducing desirable changes in the genetic material such as DNA of an organism is called genetic engineering.

Description : What is meant by biotechnology?

Last Answer : The application of technological procedures on organisms or their processes or their products to obtain new substances for human welfare is called biotechnology.

Description : What is the significance of DNA technology?

Last Answer : Knowledge of DNA technology has led us to study the possibilities of many genetically related physical and physiological problems. Knowledge of DNA technology helps in improving the quality of ... applications in the field of agriculture, health, food management, conservation of environment etc.

Description : Mention the types of mutations. How do they occur?

Last Answer : Mutations are of two types – gene mutation and chromosome mutation. Gene mutation can occur naturally or it can be induced. Mutations are due to change in the base sequence of DNA.

Description : What is meant by mutations?

Last Answer : Any change in the structure or composition of genetic materials such as gene or chromosomes is called mutation.

Description : Mention the significance of DNA.

Last Answer : a) DNA has the coded information for controlling all the metabolic activities of the cell both directly and indirectly.b) By the property of self replication, it ensures the equal ... sometimes undergoes mutation and recombination which brings about variations in the characters of the off springs.

Description : ‘Replication of DNA is a significant phenomenon’. How?

Last Answer : Replication of DNA ensures equal distribution of the genetic material to the future daughter cells.

Description : Briefly explain DNA replication.

Last Answer : DNA replication is the process of producing two identical replicas from one original DNA molecule. The process of replication begins with the breaking of hydrogen bonds between the nitrogenous bases of ... . The assembly of nucleotides on the parent DNA template is brought about by some enzymes.

Description : What is meant by DNA replication?

Last Answer : DNA replication is the process of producing two identical replicas from one original DNA molecule.

Description : Give reason: Genetic material present in the mother cell must get doubled.

Last Answer : The daughter cells produced by cell division must receive the same genetic materials in same quantity so as to resemble the parent cell. Hence the genetic material present in the mother cells must be doubled.

Description : Give reason: The two strands of DNA molecule are complementary to each other but are not identical.

Last Answer : The two strands of DNA are not identical because the nitrogenous bases are different in pairing. A purine base of one polynucleotide chain always pairs with a pyramidine base on the other. Adenine (A) pairs ... and Cytosine (C) pairs with Thymine (T). Hence the two strands of DNA are complementary.

Description : What is meant by complimentary base pairing?

Last Answer : The pairing of Adenine (A) with Thymine (T) and Guanine (G) paring with Cytosine (C) is called complimentary base pairing.

Description : Name the nitrogenous bases in a DNA molecule.

Last Answer : The four nitrogenous bases are Adenine (A), Guanine (G), Cytosine (C) and Thymine (T).

Description : What are purines and pyramidines?

Last Answer : Nitrogenous bases Adenine (A) and Guanine (G) are called purines. Nitrogenous bases Cytosine (C) and Thymine (T) are called pyramidines.

Description : What are nucleotides composed of?

Last Answer : Each polynucleotide unit consists of Deoxyribose sugar, phosphate and a nitrogenous base.

Description : Explain the Watson - Crick Model of DNA.

Last Answer : The structure of DNA molecule resembles a spirally twisted ladder called double helix. It has a pair of polynucleotide chain running anti-parallel (run parallel to each other but with opposite ... alternatively. The nitrogenous bases connect the two opposite strands like the rungs of a ladder.

Description : What are genes?

Last Answer : The thousands of hereditary units in the DNA molecule are called genes.

Description : What is centromere?

Last Answer : The chromatids are held together by centromere.

Description : What are chromatids?

Last Answer : The two parallel stands of chromosomes are called chromatids.

Description : Write the structure of chromosomes.

Last Answer : A nucleus has long, diffused and thin thread like structure called chromatin thread or chromatin network in the nucleoplasm. Chromosomes are made of two main substances proteins and nucleic acids.

Description : Explain why there is deviation in the F1 generation of the 4’O clock plants with red and white flowers.

Last Answer : Red colour is expressed only in homozygous condition and the white colour is also expressed only in homozygous condition. But in heterozygous condition both the genes express. Hence intermediate pink coloured flowers are produced.

Description : Name the type of plants obtained by Carl Correns experiment and write the phenotype ratio.

Last Answer : Carl Correns selected Four ‘O clock plant with red flowers and white flowers. In the F1 generation he obtained all pink flowers. In the F2 generation he obtained red, pink and white flowers in the ratio 1:2:1.

Description : What is incomplete dominance? Illustrate and explain Carl Correns experiment of incomplete dominance.

Last Answer : When the results of monohybrid cross and dihybrid crosses do not follow the Mendel's principles then it is called incomplete dominance. Carl Correns conducted hybridization experiments using the ... pink flowers. This was deviation from Mendelian inheritance. This is called incomplete dominance.

Description : What is meant by Mendelian type of inheritance?

Last Answer : When the results of hybridization experiments are similar to that of Mendel’s experiment then it is called Mendelian type of inheritance.

Description : Explain Mendel’s law of Independent Assortment.

Last Answer : Combinations of characters which are not present in the parental forms are produced in the next generation. When there are two pairs of contrasting characters, the distribution of the members of one pair into the gametes is independent of the distribution of the other pair.

Description : State Mendel’s law of Independent Assortment.

Last Answer : “Factors controlling separate characters normally move independent of each other during gamete formation.”

Description : Explain Mendel’s law of segregation.

Last Answer : The two pairs of factors separate during the formation of gametes. They do not blend but separate into different gametes. The gametes combine together by random fusion at the time of gamete formation.

Description : State Mendel’s law of segregation or law of purity of gametes.

Last Answer : “The pair of factors for a given character separates in equal ratio at the time of gamete formation during meiosis”.

Description : What is dihybrid cross ratio?

Last Answer : The ratio obtained in the F2 generation by crossing of two different traits of two characters is called monohybrid cross ratio. It is 9:3:3:1

Description : What is dihybrid cross?

Last Answer : A cross between two plants which differ in two specific characters is called dihybrid cross.

Description : Write the genotypic ratio of monohybrid cross.

Last Answer : 1:2:1 ( 1 pure tall, 2 tall & 1 pure dwarf)

Description : What is genotype?

Last Answer : The genetic characteristics of an organism are called genotype.

Description : Write the phenotypic ratio of monohybrid cross.

Last Answer : 3:1 (3 tall & 1 dwarf)

Description : What is phenotype?

Last Answer : The character expressed by an organism or the observable characteristics of an organism is called phenotype.

Description : State Mendel’s principle of dominance.

Last Answer : “When two factors responsible for a pair of contrasting forms of a single character come together, normally one expresses itself, while the other does not”.